The present invention relates to a device for articulating a flap to an aircraft aerodynamic surface. Although not exclusively, the articulation device according to the present invention is particularly suited to articulating spoiler flaps incorporated in housings provided in the suction face of the wings of an airplane.
In known articulation devices of this type, a flap, for example a spoiler, has its front edge facing a rear edge (for example the trailing edge or the edge of such a housing) of said aerodynamic surface (for example a wing) and the articulation device comprises at least two fittings bearing said flap projecting forward with respect to said front edge of the flap and able to pivot, under the action of actuating means (generally rams), about a common axle borne by said aerodynamic surface and arranged at the interior side thereof. Thus, said flap can adopt:
either a retracted position, for which the outer face (for example the suction face) of said flap is in the aerodynamic continuation of the outer face (for example the suction face) of said aerodynamic surface;
or deployed positions, for which said flap is turned and projects with respect to said outer face of the aerodynamic surface.
In such an articulation device, in order to avoid the slot between said rear edge of the aerodynamic surface and said front edge of said flap being too wide, as this would lead to a great deal of drag, provision is made for said rear edge of the aerodynamic surface to comprise cutouts into which said fittings can project when said flap is in the deployed position. In addition, each fitting has a blanking portion which forms an integral part of said fitting, is manufactured with it and is identical for all the fittings and which, when the flap is in the retracted position, lies inside the corresponding cutout, flush with the outer faces of the aerodynamic surface and of the flap.
Between said fittings, there is a seal, for example of the sausage type, borne by said rear edge of the aerodynamic surface and blanking off said slot there is between said front and rear edges, when the flap is in the retracted position. By contrast, between the edge of said cutouts and the blanking portions of said fittings, there is a functional clearance made necessary by the assembly and manufacturing tolerances, and that has been hitherto impossible to blank off and is the cause of aerodynamic leakage giving rise to parasitic drag.
Such parasitic drag is relatively low and is acceptable when the size of the airplane is that of conventional commercial airplanes. By contrast, in the case of very large commercial airplanes, it becomes unacceptable because the flaps are then themselves very large, especially the fittings, and the clearance needs to be large in order to absorb the assembly and manufacturing tolerances and allow said flaps to move.
The purpose of the present invention is therefore to remedy this drawback by effectively blanking off the functional clearance between said cutouts and said fittings when said flap is in the retracted position, without impeding the deployment of said flap when the latter needs to become active.
To this end, according to the invention, the device for articulating a flap to an aircraft aerodynamic surface, said flap having its front edge facing a rear edge of said aerodynamic surface and said articulation device comprising at least two fittings bearing said flap projecting forward with respect to said front edge and able to pivot, under the action of actuating means, about a common axle borne by said aerodynamic surface and arranged at the interior side thereof, in order to cause said flap to adopt:
either a retracted position, for which the outer face of said flap is in the aerodynamic continuation of the outer face of said aerodynamic surface;
or at least one deployed position, for which said flap is turned and projects with respect to the outer face of said aerodynamic surface, said rear edge of said aerodynamic surface comprising cutouts into which said fittings project when said flap is in the deployed position,
is notable in that:
the portion of each fitting facing the corresponding cutout when said flap is in the retracted position is set back toward the inside with respect to the outer faces of the aerodynamic surface and of the flap;
associated with each cutout is a flat blanking piece, the shape of which corresponds to that of said cutout;
each blanking piece is borne by a linkage articulated to said aerodynamic surface and to said flap so that:
when said flap is in the retracted position, said linkage places said blanking piece in a blanking position for which said blanking piece is arranged in said cutout, ensuring aerodynamic continuity between said aerodynamic surface and said flap; and
when said flap is in the deployed position, said linkage places said blanking piece in an outwardly offset position for which said blanking piece uncovers said cutout, allowing said flap to turn with respect to said aerodynamic surface.
As a preference, said blanking piece is fixed removably and/or adjustably to said linkage.
Thus, by virtue of these arrangements according to the present invention, the position and/or the size of each flat blanking piece can be tailored, to take account of the actual functional clearance, to the particular cutout in which it is to be housed, so as to optimize and/or minimize the slot needed between it and the edge of the cutout. To make this idea that underlies the present invention easier to implement, said blanking piece can be chosen from a set of blanking pieces of different sizes, manufactured in advance and covering the various likely clearances due to the assembly tolerances and encountered in the manufacture of the aircraft.
In one advantageous and particularly simple linkage embodiment, this linkage comprises:
at least one first connecting rod articulated, at one end, to said aerodynamic surface and bearing, at the other end, said blanking piece; and
at least one second connecting rod articulated, at one end, to said flap and, at the other end, to said first connecting rod.
Advantageously, said first connecting rod has a convoluted shape allowing it, when said flap is in the deployed position, to go around the edge of the blind end of said cutout.
To further improve the seal between said blanking piece and the edge of the corresponding cutout, provision may be made:
for the front edge of said blanking piece to bear a seal able, when the flap is in the retracted position, to blank off the slot there is between it and the edge of the blind end of said cutout; and/or
for the rear edge of said blanking piece to bear a seal able, when the flap is in the retracted position, to blank off the slot there is between it and the front edge of said flap.
Furthermore, in order to avoid the multiplicity of blanking pieces and associated control linkages, according to another particular feature of the present invention, provision is made for:
said rear edge of the aerodynamic surface to be cut away between at least two consecutive cutouts to form one global cutout;
the portion of each fitting facing said global cutout when said flap is in the retracted position to be set back toward the inside with respect to the outer faces of the aerodynamic surface and of the flap;
a flat global blanking piece, the shape of which corresponds to that of said global cutout to be associated with said global cutout;
said global cutout to be borne by a linkage articulated to said aerodynamic surface and to said flap and such that:
when said flap is in the retracted position, said linkage places said global blanking piece in a blanking position for which said global blanking piece is arranged in said cutout, ensuring aerodynamic continuity between said aerodynamic surface and said flap; and
when said flap is in the deployed position, said linkage places said global blanking piece in an outwardly offset position for which said global blanking piece uncovers said global cutout, allowing said flap to turn with respect to said aerodynamic surface.
Advantageously, the global blanking piece and said linkage may have the features of the blanking pieces and linkages described above.